--- a/ncurses/curses.priv.h
+++ b/ncurses/curses.priv.h
@@ -56,6 +56,11 @@ extern "C" {
 
 #include <ncurses_cfg.h>
 
+#if NEED_WCHAR_H
+#include <stdarg.h>
+#include <wchar.h>
+#endif
+
 #if USE_RCS_IDS
 #define MODULE_ID(id) static const char Ident[] = id;
 #else
